The present invention relates to brush making machines in general, and more particularly to improvements in a method of replenishing the supply or supplies of bristles in the magazine or magazines of a brush making machine.
Bristles which are to be introduced into the magazines of brush making machines are normally stored in the form of packages each of which contains a batch of parallel bristles and an envelope surrounding the batch. In many instances, each package is a cylinder whose length equals or slightly exceeds the length of the confined bristles and whose envelope consists of paper, synthetic plastic material or the like.
The patent to Steinebrunner et al. discloses several types of knives which can be used as a means for opening the envelopes surrounding bundles of parallel bristles prior to introduction of the bundles into the magazine of the brush making machine. As a rule, the knife is moved in the axial direction of the confined bristles, but it is also possible to move the knife radially of the normally cylindrical package. A drawback of such mode of opening the envelopes for confined batches of bristles is that the cutting edge of the knife is likely to damage at least some of the bristles as well as that the knife is likely to shift certain bristles relative to the remaining bristles of the batch; this can present problems in connection with the transport of shifted bristles through the magazine and to the inserting station where tufts containing predetermined numbers of bristles are to be inserted into the body of a brush. Still further, the cutting edges of the knives become dull after a relatively short interval of use so that the operation of the bristle feeding apparatus, or of the entire brush making machine, must be interrupted, often for extended intervals of time, in order to allow for inspection and/or replacement of the knife which is used to slit open and/or to otherwise destroy the integrity of the envelopes around the confined batches of bristles. If a dull knife is not detected in time, its envelope-opening action may not be satisfactory and this can lead to more serious malfunctions as well as to losses of substantial quantities of bristles.
Once an envelope has become separated from the respective batch of bristles, it must be removed from the machine by additional auxiliary equipment which is rather bulky, complex and expensive. Such equipment can operate properly only if the envelope of a package is fully separated from the respective batch of bristles, i.e., its operation is dependent upon the condition of the knife which is used to slit or otherwise open the envelopes.